A New Architecture for Transparent Electrodes: Relieving the Trade-Off Between Electrical Conductivity and Optical Transmittance

Department of Materials Science and Engineering, Iowa State University, Ames, IA 5001, USA.
Advanced Materials (Impact Factor: 17.49). 06/2011; 23(21):2469-73. DOI: 10.1002/adma.201100419
Source: PubMed


A novel architecture with high-aspect-ratio nanoscale metallic periodic patterns is fabricated as transparent electrodes. The structure shows high visible light transmission and has superior electrical conductivity compared to standard indium tin oxide (ITO) coated glass. A proof-of-principle organic photovoltaic device is successfully fabricated with the electrode.

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Available from: Kristen Constant, Jan 14, 2014
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    • "To overcome the drawbacks of the ITO transparent electrodes , and due to the high conductivity and high bending tolerance of metals, metal nanostructures based transparent electrodes including ultrathin metal film [2] [3], nano grid arrays [4] [5] [6] [7], random metal nanowires[8] [9] [10] [11] [12] [13] [14] [15] [16] [17], nanotroughs [18] and nanomeshes [19] [20] [21] [22] [23] [24] have been extensively studied both theoretically and experimentally, this has demonstrated high transmittance and low sheet resistance which are comparable to ITO based transparent electrodes. Simultaneously, solar cells integrated with metal nanostructure transparent electrodes have also been proposed and studied [8, 25–31]. "
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    ABSTRACT: We present the design of an organic solar cell (OSC), integrated with nanohole patterned aluminum electrode with hexagonal lattice and analyze the light absorption mechanism in detail. The periodic nanohole pattern in the electrode excites a resonant waveguide mode which localizes the electromagnetic fields into the active layer at the long wavelengths where the active material usually has a relatively low absorption coefficient. The calculated maximum achievable photocurrent density indicates that OSC integrated with nanohole patterned aluminum electrode shows slightly better performance compare to that of the conventional OSC integrated with an indium tin oxide electrode. Moreover, the waveguide mode can be tuned by varying the period of the nanohole array and the thickness of nanocrystalline zinc oxide for different kinds of cell structures. By combining with other strategies to enhance the absorption at the short wavelength, our finding provides a promising way to further improve the efficiency of the OSCs.
    Full-text · Article · Aug 2015 · Journal of optics
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    • "This trade-off has currently been investigated in Refs. [8] [9]. However the primary research focus was concentrated on the uniform patterns while little attention has been paid to the random ones. "
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    ABSTRACT: The distinction of opto-electrical properties in case of aluminum , gold and silver random and ordered nano-holed layers was demonstrated. It is found that transmittance is dropped due to the shortening of plasmon polaritons propagating length within the Anderson localization effect, while sheet resistance increases in regard of decrement of metal connections volume. Eventually gold and silver possess the transmittance of more than 80% and the sheet resistance of 20 Ohm/sq regardless of holes arrangement. Al-iminum demonstrates comparable parameters only with ordered patterns.
    Full-text · Conference Paper · May 2014
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    • "In recent research efforts, carbon nanotube networks [10] and unpatterned thin metal films [11] have been evaluated as potential replacements for the conventional ITO electrodes. However , these TCEs still suffer from the classic tradeoff between the optical transmittance and electrical conductivity [12]. An increase in the thickness of the film results in a lower electrical sheet resistance due to the increase in the number of charge carriers , which improves the electrical performance. "
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    ABSTRACT: In this paper, we propose a circuit model for two-dimensional arrays of metallic square holes located on a homogeneous substrate, in order to propose a new scheme containing this type of metamaterials to obtain transparent electrodes with simultaneous terahertz transparency and low electrical resistance. The results of the introduced circuit model, which is a fully analytical model with explicit expressions, are in almost complete agreement with the full-wave simulations. Thanks to this analytical model, we can employ standard binomial matching transformer in order to minimize the reflected power from the structure at a desired frequency. Furthermore, taking advantage of this model, we design an optimized tri-layer structure by seeking for a high optical transmittance at the desired frequency and over a wide bandwidth. The obtained transparent electrode has a high power transmission (more than 85%) within a wide frequency range (48% of the central frequency) which is desirable in commonly used transparent electrodes. The square holes are perforated in thick metallic slabs which drastically reduce the electrical resistance of the structure.
    Full-text · Article · May 2014 · IEEE Transactions on Terahertz Science and Technology
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